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Subject: Re: If you like to crush easy mate...

Author: leonid

Date: 11:40:37 02/10/01

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On February 10, 2001 at 13:27:32, Uri Blass wrote:

>On February 10, 2001 at 12:43:05, leonid wrote:
>
>>On February 10, 2001 at 12:00:30, Uri Blass wrote:
>>
>>>On February 10, 2001 at 11:08:17, leonid wrote:
>>><snipped?
>>>>What is the "ss=10" ?
>>>
>>>ss is the selectivity search parameter of chessmaster.
>>>
>>>I know from experience that chessmaster is usually faster in solving problems if
>>>I give it bigger selectivity.
>>>
>>>The default value is 6 and the maximal value is 10.
>>
>>Probably it is the maximum number of moves to see in each ply. When mine solved
>>this position this variable was at 6.
>>
>>Leonid.
>
>It is not.
>
>I believe that it is about null move pruning.

If it is really so, my guess is completely wrong. I even feel me sure that null
move in mate solutions is the wrong way to proceed. It should lead to mistakes.


>Chessmaster shows two depthes.
>The first number is usually small(1 in the first iterations).
>The second number is bigger when the difference between them is not more than
>the selectivity.

I am lost.

>I guess that Chessmaster does not use the null move pruning in the first plies
>but it is using null move pruning everywhere in the tree later.

As I said before, after the description of the null move that I have read here,
null move should lead to mistakes. Since Chess Master is very good in solutions
of mates, I presume that he do something different. It could be that somebody
could indicate what it really is.

>I believe that when chessmaster shows depth 1/4 it means that it looks at
>everything at depth 1 in the tree.

>It also looks at everything at depth 4 except move that it prunes because of
>null move pruning and it also does a lot of extensions so it can practically see
>mate in 10 at depth 1/4.
>
>I know from experience that chessmaster waste a lot of time on stupid lines if I
>give it a low selectivity because it does not prune lines with no threat.

Problem with all those stupid moves is that sometime they are the best one.
I remember Chess Master 4000 as impecable solver but not the quickest one.
I prefere impecable to quick and buggy.

Leonid.

>Uri



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